The patients at Louisa Guidotti hospital said there were eight men, one carrying a shotgun, another with an AK-47, others with pistols, and they went from bed to bed forcing out anyone who could walk.

Nurses were dragged away from the sick. Motorists driving by the hospital, 87 miles north-east of Harare, were stopped and taken from their cars.

About 70 people were gathered in the grounds. Then the lecture began. "This is your last chance," said one of the armed men. "You messed up when you voted. Next time you vote you must get it right or you will die."

One of the men selected people to stand and shout slogans of Zimbabwe's ruling Zanu-PF party and to sing songs from the liberation war . Those who did not do so enthusiastically were beaten. Another cocked his gun and told the crowd to point out opposition supporters.

Sandati Kuratidzi lives on the hospital grounds because his wife is a physiotherapist there. He is an activist with the opposition Movement for Democratic Change which stunned Zanu-PF by apparently defeating Robert Mugabe in the presidential election, although the electoral commission has still to release the official result 12 days later.

When Kuratidzi saw the pick-up with the armed men draw up, he knew what was coming and hid on top of a cupboard.

"They warned people that if they voted for the opposition they would be killed. They had AK-47s, shotguns, guns in their belts. People were very afraid," he said. "They were saying they were going to show an example to anyone supporting MDC and they asked the people to point out who they were but no one did. Their behaviour was inhuman."

Then the men piled back into their truck and set off for the next village.

Mugabe has unleashed his shock troops, Zanu-PF's militias and those who call themselves liberation war veterans even though most are too young to have fought it, in an undeclared campaign of terror against rural voters in advance of an expected second round of presidential elections.

The violence and intimidation that helped deliver perverted election victories to Zanu-PF three and six years ago were absent from the presidential and parliamentary ballot on March 29, and Mugabe lost. Now they are returning with a vengeance and the ruling party is using results from the first round as a guide to where to exert pressure.

Across provinces such as Mashonaland, Manicaland and Matabeleland, where the opposition campaigned freely for the first time and made strong inroads into Zanu-PF's support, armed gangs move from village to village, forcing people to meetings and threatening dire consequences if the vote goes against Mugabe again. Opposition supporters are identified and beaten or driven from their homes.

The MDC said Mugabe, who during the election campaign said he regarded it as a war, was delaying the release of the presidential ballot in order to wage his terror campaign before a run-off is formally declared and foreign monitors return. The opposition said it feared the threats were working.

The intimidation is following a pattern seen in earlier elections. It began with assaults on scores of white-owned farms at the weekend. War veterans drove white families from their land as Mugabe once again sought to characterise the election as a struggle against British imperialism. But the assault on the white farmers is a cover for a broader campaign against black voters. The MDC has made public a document it said was from a disaffected senior military officer listing the deployment of 200 army officers to coordinate the strategy on the ground.

Louisa Guidotti hospital is in Mutoko East constituency in Mashonaland East, once a Mugabe stronghold where Abel Samakande was the MDC's parliamentary candidate. Samakande lost but made strong inroads into traditional Zanu-PF territory, picking up about 42% of the vote.

Now that achievement is coming back to haunt those who supported him. He said the first indication he had of the return of the terror tactics was when he was tipped off by friends in Zanu-PF that he was being hunted.

"They told us there was a meeting at which it was decided to eliminate one of the local MDC leaders. Our friends in Zanu-PF warned us not to sleep in our houses, to move in groups," he said. Then he had a call telling him that armed men had descended on the village of Matsande.

"When we heard about these armed men we went to the police for assistance. The officer in charge said he could not help," said Samakande.

The MDC candidate headed to Matsande, but by the time he reached it, the men with guns had done their work and moved on to the hospital and then the village of Mushimbo. "On the way they got to a township where they forced all the shops to close and forced everybody to a meeting," he said. "When I got home I was told by my wife there were men who came to the place. She kept the door locked and they left. We decided not to sleep there for fear of our lives."

Yesterday, other armed men backed by Zanu-PF activists went to Mutoko and forced people to a meeting. A man in the crowd identified two MDC supporters. They were marched to the front and beaten so badly that they were left with broken bones. The group then went to the houses of known MDC supporters and chased them from the town.

It is a pattern repeated across Mashonaland in the north to parts of Matabeleland in the south, where about 60 families were expelled from their homes in Insiza yesterday after Zanu-PF identified them as having voted for the MDC from the election count for their local polling station.

In Gweru, opposition supporters have been attacked by soldiers, according to the Zimbabwe Peace Project. "Soldiers descended on unsuspecting revellers in bars and late night shoppers, beating them up. The soldiers were allegedly saying the people's crime among other things was that they did not vote correctly," said the ZPP. In Mutare, gangs armed with whips and knives have been going house to house in search of MDC supporters. In Manicaland, at least one activist has been killed. In Chimanimani East, opposition supporters have been burned from their homes.

Milton Kanomakuyo,the MDC parliamentary candidate for Mudzi South in Mashonaland, was taking his nine-year-old daughter to hospital on Tuesday when he was stopped by a friend. "He told me he saw Zanu-PF milling around, stopping people, hunting for known MDC activists," Kanomakuyo said. "In the evening a guy who works for the ministry of education who was an election officer in Mudzi South came to my shop and told me about these people: eight war vets with AK-47s in Mazda pick-up trucks."

The armed men had already visited Kotwa. "They ordered people out of buses, out of shops, gathered them together," he added. "One of the men was cocking a rifle to scare people. They told the people they'd messed up by voting MDC and they weren't going to let people make that mistake again. They said they wouldn't entertain even one opposition vote. They told people to shout slogans and those who couldn't do it were slapped.

"When they were campaigning, they were telling people over and over again that if Zanu-PF loses there will be a war. Now they are reminding them."

Samakande said the threats to kill opponents showed the MDC as powerless and would cost its candidate, Morgan Tsvangirai, in a second round election. "When they give you a warning people take it seriously. If we are going to have a run-off we will not win and it's going to be bloody because they know in a free and fair environment they will not win."

Kanomakuyo agreed: "A friend in the police said to me that if we go for the run-off the villagers will be afraid to vote for the MDC. I think they will be. I'm sure they are going to do this for quite some time. By the time the results come out people will be terrified. It's going to be difficult to stop this. If we try to do mass action definitely it will be crushed."